Unicode chart 2100-214F. [w:] Character 2114 of the Unicode 6.0 and 5.0 standards [on-line]. Unicode Consortium. [dostęp 2012-07-24]. (ang.).
worldcat.org
Ronald EdwardR.E.ZupkoRonald EdwardR.E., Medieval Apothecary Weights and Measures: The Principal Units of England and France, „Pharmacy in History”, 32 (2), 1990, s. 60, ISSN0031-7047 [dostęp 2022-04-09].